Grinding machine work clamping mechanism



April 5, 1938. H. A. slLvl-:N Er AL 2,113,388

GRINDING MACHINE WORK CLAMPING MEGHANISM l v Filed 1396.24, v193:5 ssheets-sheet 1 H. A. SILVEN ET AL GRINDING MACHINE WORK CLAMPINGMECHANISM April 5, 1938.

Filed Dec. 24, 1956 5 Sheets-Sheyet 2 Hawaii/27'v A.S/L VEN CARL G'.FLYGARE MM5-m3 u ZZM FG.A Z

April 5, 1938. H. A. slLvEN l-:T A1.

GRINDING MACHINE WORK CLAMPING MECHANISM Filed Deo. 24, 1936 5Sheets-Sheet 4 l 23 4 Y V H913 IN )HERaERTA.5'/LVEN CARL GFLYGARE @wwwApril 5, 193s. H. A. SILVEN ET AL 2,113,388

GRINDING MACHINE WORK GLAMPING MECHANISM Filed Dec. 24, 1936 5Sheets-Sheet 5 43` HG'. .Z 5

HERBERT A. SIL VEN CARL G'. FLYGARE PatentedA Apr. 5, 1938 -UNiTEosTATEsPATENT OFFICE GmNDING MACHINE WORK CLAMPING MEoHANlsM f .ll-Ierbert A.Silven and Carl G. Flygare, Worcester', Mass.,

Worcester,

setts assignors to Norton Company, Mass., a corporation of Massachu-Application December 24, 1936,A Serial No. 117,652

'13 claims. (o1. '51;237)

trically actuated work clamping mechanism. A

further object of the invention is to provide an electrically actuatedcam locked clamping mech' anlsm for a work piece. l A further object ofthe invention is to provid opposed electrically actuated, cam lockedclamping mechanisms for simultaneously clamping the opposite ends of awork piece in position on opposed synchronously rotated woik Asupportingspindles. Other objects will be in part obvious or in part pointed outhereinafter.

The invention accordingly consists in the -features of construction,combinations of elements, 0,-, and arrangements of parts, as will beexempli- `fled in the structure to be hereinafter described, and thescope of theapplication of which will be indicated in the followingclaims.

-ln the accompanying drawings, in which is shown .one of variouspossible embodiments ofthe mechanical features of this invention,

Fig; 1 is a fragmentary longitudinal sectional view, showing the opposedwork supporting and rotating heads and the driving and clampingmechanisms therefor;

Fig. 2 is a fragmentary view of` various mechanisms and controls for themachine, together with an electric wiring diagram;

Fig. 3 is a fragmentary longitudinal vertical 40 sectional view, on anenlarged scale, taken work head, as shown in through. the right-handFig. l;

Fig. 4 is a fragmentary longitudinalv vertical sectional view, on anenlarged scale, of the right- 45' hand work clamping head and itssupporting spindle;

Fig. 5 is an end elevation of the right-hand work head, as shown in Fig.4;

Fig. 6 is a cross sectional view, taken approximately on the line 6--6of Fig. 5, through the right-hand work head;

Fig. 7 is a fragmentary sectional view, taken approximately on the line1 1 of Fig. 3, showing the synchronizing adjustment for the spindledriving mechanism;

trolled by the operator.

'.Fig. 8 is a fragmentary detail view, taken approximatelyon the line8-8 of Fig. 10, showingv the mechanism for limiting Athe rotary movementof thev cam for actuating the work clamping jaws; v

Fig. 9 is a fragmentary longitudinal vertical sectional view, on anenlarged scale, through the left-"hand work. head, showing thecrankshaft in dexingmechanism;

Fig. 10 is an end elevation of the left-hand' work holder, with thecrankshaft indexing mechanism removed;

Fig. lil is an end elevation of the 4left-hand work head, with thecrankshaft indexing mechanism in operative position;

Y Fig. 12 is a horizontal sectional view, taken approximately on theline IZ-I? of Fig. 11, through the left-hand work head;

Fig. 13 is a fragmentary detail View, on an enlarged scale,- takenapproximately on the line l3-I3 of Fig. 11, of the index pawl;

Fig. 14 is a sectional view, on an enlarged scale, taken approximatelyon the line VM-M of Fig. 3, showing the hammer-blow mechanism forclamping and unclampinga work piece;

Fig. 15 is a fragmentary sectional view, on an enlarged scale, takenapproximately on the line |5--I5 of Fig. 14, throughl the gear mechanismgrinding machine in which two opposed work supporting heads are providedwith clamping mechanisms to support and to rotate synchronously the workduring the grinding operation. In the form illustrated, a clampingdevice for holding the Work during rotation may comprise a rotatableholding member and a clamping jaw which is` movable into engagement withthe periphery of an end of the work by a power mechanism con-'- Theclamping jaw may be moved by an electrically operated mechanism intoengagement with the work, and it may be similarly released fromengagement after the grinding operation has been completed. The

work is positively rotated by means of a motor driven mechanism and inorder that the clamping jaw may not be released until the work rotationhas been stopped, and vice versa, the controlling mechanism for themotor and the clamping jaw 'are so interlocked and arranged that theymay be operated only in a. definite sequence.

The double head crankshaft grinding machine illustrated in the drawingscomprises a longitudinally movable work supporting table 20 which isadapted to slide longitudinally on a V-way 2| and afiat way (not shown)on the base 22 of the machine. The table 20 is adapted to support a workblank, such as a crankshaft 23,` in operative relation with a rotatablegrinding wheel 24 (Fig. 9) which may be mounted on any' of the old andwell known types of wheel slides, such as are common, wellknownexpedients in grinding construction. The wheel slide is providedwith a suitable feeding mechanism (not shown) so that' the grindingwheel 24 may be fed into the work to grind the same to the desired size.

'Ihe work table 20 is provided with a pair of work supporting heads '21and 28 which may be formed integral with the table 20 or may beadjustably clamped thereon so that the heads may be moved laterally ofthe table to align the axis of one head relative to the axis of theother head and may further be adjusted longitudinally, one relative tothe other, to accommodate various lengths of crankshafts.

The heads 21 and 28 are provided with work supporting spindles 29 and 30journalled in bearings 3| and 32 in the heads 21 and 28, respectively.'I'he work supporting spindles 29 and 30 are rotated by the sprockets 35and `38, respec,

tively, which are connected with sprockets V31 and 38 by link drivingchains 39 and 40, respectively. The sprocketsv 31 and 38 are mounted ona rotatable drive shaft 4| which ismounted in bearings 42 and 43depending from the table 20. It will be seen from this construction thatany rotation of the shaft 4| will be transmitted through the sprocketsand chains -to drive the Work supporting spindles 29 and 30. The shaft4| 'may be driven by a power driven driving mechanism, such as anelectric motor 45 (Fig. 2).

. The motor 45 is supported on the rear of. the

machine base 22 and is connected by driving belts 46 with a pulley 41mounted on` a drive shaft 48. The other end of the drive shaft 48 isprovided with a sprocket 49 kwhich is connected by a link chain 50 withasprocket .5| which is slidably keyed to the shaft 4| by means of 'thekeys 52 and 53. The sprocket 5| may be heldA against endwise movement bymeans of-yoked bracket 54 asthe table 20 and the shaft 4| are traversedlongitudinally.

It is desirable in a machine of this type to provide a suitablecontrol'mechanism for stopping and starting the rotation of the workspindles 29 and 30. In the preferred construction, an

velectrically operated mechanism is provided, such as an electricstarting switch which serves to start the rotation of the motor 45 whendesired.

vwork supporting and clamping heads 51 and 58 are secured. `Each of theheads 51 and'58 is provided jwith fixed work supporting and locatingbearing members 59 and 60, respectively, adapted to support one of theend bearing portions 6| and 62 of the crankshaft 23. The surfaces of thebearing members 59 and 60 are arranged to support and align thecrankshaft 23 for a grinding operation. v

. Describing the left-hand work head 51 (Fig. 10) a lever 65 ispivotally mountedv on a stud 66 on the work head 51 and is provided atits outer endwith a projecting stud 61 having a work bearing member 68loosely mounted on the end thereof. The stud 61 is screw threadedthrough the end of the lever 65 and is arranged so that it may be lockedin adjusted position by means of a lock nut 69. The other end of thelever 65 is provided with a non-rotatable follower roller 10 which ismounted on a stud 1| carried by the lever 65. The roller 10 is arrangedto engage the periphery of a rotatable cam 12 vwhich is mounted on theend of a rotatable shaft 13 which is` rotatably supported in bearings 14and 15 in the head 51. The cam 12 is arranged to lengage the roller 10,and serves when rotated to rock the lever 65 so as to rigidly clamp thecrankshaft 23 within the head 51. A spring 16 interposed between a stud11 on the arm 65 and a stud 18 carried by thehead 51 serves to rock thelever 65 so as to maintain the follower roller 10 in operativeengagement with the cam 12 when it is rotated. The cam 12 is actuated bya mechanism to be hereinafter described which rotates a shaft within thespindle 29. A gear 8l is mounted on the outer end of the shaft 8 0 andmeshes with a gear 82 mounted on the shaft 13,

so that whenvthe shaft 80 is 1'otated, the rotary motion will betransmitted through the gear 8|,

the gear 82, the shaft 13, and the cam 12, to rock the lever 65 andthereby clamp or release a lcrankshaft .23 in the head.

acomplete rotation Sof the cam. The gear 821s provided with a projectinglug A83 which is arranged in the path of a lug 84 projecting from aplate 85 xed to the head' 51 (Figs.8 and 10).

'I'he Work head 58 is constructed substantially y identical to the workhead 51 as above described.` A'I'his head is shown in Figs. 4, 5 and 6and comprises a lever pivotally mounted on a stud 96 on thework head 58.'I'he lever 95 i's-provided at its outer end with a projecting adjusting-screw 91 having a work bearing shoe 98 loosely mounted von the endthereof. 'I'he screw is .threaded through the end of the lever 95 and isarranged so that it may belocked in adjusted position by means of a locknut 99. The other end of the lever 95 is provided with a non-rotatablefollower roller |00 which is mounted on a stud |0| carried by the lever95. The roller |00 is arranged to engage the periphery of a rotatablecam |02 which is mounted on the end of a rotatable shaft |03. The shaft|03 is rotatably supported in bearings |04 and |05 in the work head 58.The cam |02 is arranged to engage the roller |00, and serves whenrotated to rock the lever, or clamping jaw 95 so as to rigidly clamp thecrankshaft 23 within the head 58. A spring. |06 interposed between astud |01 on the arm 95 and a stud |08 carried by the head 58 serves torock the lever 95 so as to maintain the follower roller |00 in operativeengagement with the cam |02 when it is rotated. The ca'm |02 is actuatedby a mechanism to be hereinafter described which rotates the shaft ||0within the spindle 30. A

gear I I is mounted on the outer end ofthe shaft IIO and, meshes with agear I I2 mounted on the-` shaft |03, so that when the shaft l |0` isrotated, the rotary motion is transmitted through Ithe gear III, thegear H2, the shaft |03, and the cam |02, to rock the lever 95 and.thereby clamp Qr release the crankshaft 23 in the head 58.

The cam |02 'is also arranged so that lit can be rotated only through apartial turn. A lug |I3 projects from vthe gear ||2 and is `arranged inthe path of a lug .I I4 projecting from the plate I|5 fixed to thevhead58 (Figs. 5 and 6). `The lug ||4 serves to restrict the rotarymovement'of the cam |02.

- In the grinding of a crankshaft having two cr.

more pins arranged on the same axis, it is customary to grindthealignedcrank-pins and then to index the crankshaft by a rotary motion tobring another set of crankpins'intoF axial alignment with the axis oftherotary work head for a grinding operation. It is, therefore, desirableto provide an indexing mechanism whereby* the"VA crankshaft may bereadily inserted in the machine and readily indexed to bring successivecrankpinsdnto a grinding position. 'I'he 'lefthand work head is providedwith anl indexing mechanismcomprising a rotary plate |20 which is heldin position on the head -51 by means of af c-shaped annular flangedlmember |2| which is fixed on the work head 51. The index plate isprovided with a plurality of nohes |22 which are arranged to be engagedby an index or stop pawl |23 which is pivotally mounted on a' stud |24sup=` ported in the member I2I. The index plate |20 is providedwith alocating lug |25 which is arranged to be engaged Lby alocating lug |28on the crankshaft 23. When the, crankshaft 23 is inserted in the workheads 51 and 58,'the index plate |20 is-turneduntil a notch |22 engagesthe pawl |23 to locate the index plate in its initial position, and thecrankshaft 23 lis rotated to Y bring the lug .|28 on the' shaft intoengagement with the lug |25 on` the index plate |20, and

g the shaft isv then clamped in position by means and the. crankshaft 23and the index plate v|2i'l are indexed to bring the nextset of crankpinsinto A axial alignmentwith'the axis of rotation of the heads 51 and 58.l

An electrically operated mechanism is provided for actuating the cams 12and |02- to synchronously actuate the clamping jaws 85 and 35 to rigidlysecure opposite ends of a crankshaft 23 in an operating position on theheads 51 and 58. `I'heelectric actuating mechanism may comprise a pairof electric motors |30 and |3|;v'v'h`ich` are of a high torque, totallyenclosed type from Vwhich power is transmitted from an armature'sha-i'tI 351 through a reduction gear unitto rotate theshaft 80 and ||0toactuate the work clamping mechaing the work dueto awedgingaction-between the clamping cams and the clamping rollers, a un'que`hammer-blow mechanism. is provided which serves to operate throughprojecting lugs in the gear mechanism'so that the motor has anopportunity to pick up speed when operated to clamp or unclamp the workpiece before the hammeractuating the shaft blow takes place to ylock orrelease the clamping cam from a clamping or unclamped position.

The gear unit between the motors |30 and |3| and the shafts 80 .and |I0,respectively, is subsgintially identical; consequently only one of t eseunits has been illustratedin detail (Figs. 13, 14 and 15).l'I'heelectric motors |30 and |3|y are rotatably mounted within enclosedcasings |33 and |34 projecting from the opposite ends of the table 20.The motor |3| is provided with an armature shaft |35. A gear |36 ismounted on the outer end of the armature shaft |35 and meshes with agear |31 which is mounted on a rotatable shaft |38 journaled in a A ame|30. 'I'he shaft |38 carries a gear |40 whi h meshes with a gear |4|rotatably mounted on a shaft |42. 'Ihe shaft |42 also carries a gear |43meshing with a gear |44. The gear |44 is rotatably mounted votra eeve|45 which is rotatably supported on bear! gs |45 and |41 in the casings|48 and |39 respectively.

.iecting lug |48 which'is arranged in the path of Aan outwardlyprojecting lug |50 projecting from the sleeve |45. ese lugs serve toallow, through thereduction gearing, several rotations of the armatureshaft |35 before the lug I49Ycarried by the gear |44 rotates so as toengage the lugv |50. 'I'hese two lugs serve as a hammer-blow apparatusto'release the cam 12 or |02 from a locked or clamped position withoutputting an undue burden on theclamping motors; The outer end of theshaft is formed as a splined shaft Ahaving projecting splines therefromwhichV engage and mesh with a correspondingly shaped aperture |52 withinthe rotatable sleeve |45, so that any rotary motion of the sleeve |45 bythe motor |3| servesto transmit a rotary motion to they shaft ||0 whichin turn, through the gears and I|2, serves to rotate the clamping cam|02 to clamp or release a crankshaft 23 in the head 58. An identicalmechanism is provided for 80 so as to simultaneously clamp the oppositeend of the shaft into an operating position on the head 51. Since thesemech- The gear |44 is provided with an inwardly proanisms 1areidentical, it is not believed to be nec- Y .essary to illustrate anddescribe both in detail.

'Ihe splined connection between the shafts 80 and I0 and theirrespective clamping motor units |30. and |3|, respectively, allows thework heads 21 and 28 to be adjustedy longitudinally on the table 20without disturbing the driving connection between the driving motors |30and |3| and the clamping mechanism on the heads 51 spectively. v

Similarly, it is desirable to provide a. splined connection in the drivefor the work rotating spindles 28 and 30 sothat the drive to the spindleis not interrupted 'or disconnected by a longitudinal aldJustment of theheads 21 and 28. A sleeve |55 is slidably keyed by a key |56 to thespindler30l1 The key |55 slides longitudinally in an elongated keyway|51 within tlie spindle 30. The driving sprocket 35 is connected torotate th'e and 58, re-

Y ysleeve |55. A similar construction is provided for driving thespindle 28. A sleeve |58 is intery posed between the spindle29 and thesprocket 35. nism. In order to prevent diiii'culty in unclamp- In orderto prevent torsional strains being set up in the work table or fixedpart ofthe machine due to the clamping operation; it is desirable tomount the clamping motors |30 and I 3| so that they revolve with thespindles 29 andv 30 during the grinding operation. i

In order to accomplish this result, the outer end of the sleeve |55 ismounted in a bearing 2| 0 which is supported in a bracket 2| I which isfixed relative to the table 20. The bearing 2|0 serves as a radial andthrust bearing -support for the outer end of the sleeve I 55. 'I'hesleeve |55 carries at its outer end a plate 2|2 to which is secured acasing |48 ofthe reduction gear unit. The motor |3| is fixedly mountedto the casing |48 so that the motor |3| rotates with the casing |48, thesleeve |55, and the spindle 30 during the grindingv operation. When thespindles 2,9 and 30 are stopped during the unloading period,thefarmature shaft |35 oi the motor |3| may be rotated, as abovedescribed, to clamp or release a work piece from the heads 55 and 55. -Asimilar mounting is provided for Supporting the motor |30 so that itrotates with the spindle 28 during the grinding operation. Since thismounting is substantially identical to the mounting for the motor |3|above described, it is not deemed necessary to illustrate or describethis arrangement. in detail.

In order to .align the work heads 51 and58, that is to adjust themangularly relative to each other in setting up the machine, it isdesirable to provide an adjustment for at least one of the heads so thatthe heads may be aligned and any bocklash between the driving chains andthe sprockets may be eliminated so that a uniform synchronous movementmay be obtained to each of the heads 51 and 58. This is preferablyaccomplished by providing a rotary adjustment for adjusting the gear 35relative to the sleeve |55. 'I'he gear 35 is rotatably mounted on sleeve|80 which is interposed between the gear 35 and the sleeve |55` Thesleeve |50 is locked to the sleeve |55 by means of a'key II5|. A pin'|52 is ,keyedto the sprocket 35, and is provided with a square head |53.The sleeve |50 is provided with an integral flanged member |54 havingelongated slots |55 provided therein. Clamping screws |88 pass throughthe elongated slots |55 and are screw threaded into the gear or sprocket85, thus permitting a rotary adjustment of .the sprocket 35 relative tothe sleeve |55. By loosening the clamping screws |55, andadjustingtheopposed push and pull screws |51 and |58 (Fig. '1), the flange |54 maybe adjusted angularly relative to the gear or sprocket 35, as desired.After the 4desired adjustment has been made, the ange |54 may be clampedin adjusted position to the sprocket 35 by tightening Y the clampingscrews |55.

The work clamping `motors |30 and |3| are of the reversible type and arearranged so that when the armature shaft rotates in one direction, thereduction gear mechanism above-described serves to rotate the clampingcam in a direction to clamp the crankshaft 23 in operative position onthe machine. When the current to the motors |30 and |3| is reversed,through the reduction gear mechanism, the clamping cams on each of theheads 51 and 58 are rotated in the reverse direction and the releasedtension of the springs 18 and |05 serves torock `the clamping arms'85and 95 to release or unclamp the crankshaft. A lever actuated drum typereversing switch |58 is pro` vided toxcontrol-the direction of rotationof the clamping motors. The reversing switch |58y is controlled, by amanually operable lever |10. When the control lever 10 is moved intoposition ln' the electric circuit is completed to rotate the motors |30and |3| in a direction to actuate the clamping jaws 55 and ,85 to clampa crankshaft 23 in an operative position to the work heads 51 and 58.Similarly, when the lever |10 is moved into position |10b, the currentin the motor circuit v is reversed to reverse the direction of rotationthereof and to unclamp or release the clamping jaws so that the groundwork piece may be read-ily removed'from the machine.

It is desirable to Iprovide a safety interlock which will preventrotation of the work clamping motors |30 and |3| in either directionunless the main control lever |80 is-.in a work clamping position, `soas to prevent releasing the crankshaft from the machine when the workheads arel rotated or vthe table or wheel slide is in a feedingposition. ,A normally open limit switch |1|`havingan actuating roller|12 is connected so th'at when the main control lever |80 is in aclamping position, as shown4 in fulllines in Fig. 2, a lug |13 on thelever |80 serves to close the limit switch |1| which in turn serves toactuate a .relay or magnetic switch |14 to render the reverse switch |59operative. When the lever |80 is rocked away from the positionillustrated in Fig. 2, that is, in a counterclockwise direction, the lug|13 recedes'from the roller |12 and allows the limitswitch |1| to openwhich in turn opens the relay or magnetic switch |14 and thereby cutsoil' the current to the reversing switch |59, thereby rendering the workclamping motors |30' and |3| inoperative.

It is also desirable to provide a further interlock which serves toprevent starting the work rotation motor 45 except when the work clampshave been actuated to grip a work piece 23. A limit switch |15 ismounted so as to be actuated by and in timed relation with the.reversing movement of the lever |10 'of the reversing switch |59. Thelimit switch |15 is provided with an actuating roller |15.` A cam |11 iscarried by a rotatable member having downwardly projecting lugs |18 and|19 which lie in the path of the lever |10 of the reversing switch |59(Figs. 2 and 17). In the position of the limit switch |15 and itsassociated parts, the limit switches |84 and |15 are in series with eachother and are connected so that when'eitherl of the limit switches isopened, the solenoid |85 is deenergied and the tension of the spring |85holds the trip switch |92 in an open position so as to prevent startingof the work rotation. When the lever |80 is moved into the positionillustrated in Fig. 2, the cam |82 carried thereby contacts the roller|83 and opens the limit switch |84, thus breaking the circuit andrendering the solenoid |85 ineffective. In this position of the parts,the` lever 110 of the reverse switch |88 may be moved to clamp orrelease a work piece in the work heads 51 and 58.

In order that the work holders 51 and 58 may be automatically stoppedVin a predetermined vertical or upright position for loading, a suitablemechanism (Fig. 2) is provided which is operated in timed relation withthe control mechanismso that when the main control lever, pivotallymounted on-a stud |8| (Fig. 2), is shifted after a crankpin has beenground to movethe steadyrest and wheel slide Lto an inoperativeposition, a cam |82 carried by the lever `|80 engages a roller |83 of anormally closed limit switch |84 to open the same. The limit switch |84breaks the circuit to deenergize a solenoid |85l which is mounted on therear of the table 20. The deenergizing of the solenoid V|85 releases thetension of aspring 85 which serves to rock an arm |81 into the positionillustrated in Fig. 2 to move a roller |88 carried by a yoke |89 on theend of a slidably mounted rod |90, so that the roller |88 `rides uponthe periphery of a cam |9| which is 2,113,388 mounted on sleeve |58 torotate with th worksupporting spindle 29.-

` The motor 45 for rotating the work supportin spindles 29 and 30 ispreferably of a type which is controlled by a magneticl reverse starterswitch and a motor 'brake switch |95 so that the rota-' tion of themotor may be stopped in 'a' predetermined position after a grindingoperation has` the control lever |80 is shifted to stop the workrotation at the end of a grinding operation, the

normally closed limit switch 8 4 .is opened by.

movement of. the lever 80, which serves to deenergize the' solenoid |85,allowing the follower roller |88 to move into contact with the cam |9|.

The movement of the follower roller |88-into operative contact with thecam 9| serves to open a normally closed trip switch |92 which opens thecircuit and cuts the power from the power .eld' of the electricmotor`45. This'breaking of the circuit in the power iield serves througha motor brake switch |95 to actuate a magnetic reverse starter switvch,which s erves instantaneouslyto reverse the current in the motor and,through the motor brake switch |95, to stop the motor-45, spindles 29and 30 and work heads 51 and 58'in a predetermined position each timethe work rotation is stopped. -When the solenoid |85 is deenergized, thefollower roller |88 is moved into `operative engagement with theperiphery of the cam |9| and the normallyclosed trip switch |92 remainsclosed until the follower roller |88 rides.

into the'low point or depression |94 of the cam |9| which serves throughan. arm |98 andan adjustable screw |91 carried thereby to engage theplunger |98 of the trip switch |92 to open the switch and thereby cutoff `the power from the power field of the motor 45. A safetyswitch 202ismounted in the power line and serves to render the circuit inoperativein case the electric current fails. If the electric current supplied tothe driving motor 4'5 fails, the switch 202 opens, and before the Workrotation can be again started, the reset push'button 203l must be pushedto close the circuit which in turn serves to close the safety switch 202and therebyA again start the rotation of the motor 45. A push.

button 204 serves as a jogging "switch to jog the rotation of the workholder, if desired. 'I'he snap switch 205 in the power circuit serves inone Vposition to permit a jogging of the work rotation by the pushbutton 204 or in the opposite position serves to start the rotationofthe motor 45.

A snap switch 200 in one position serves to render toward the right asviewed in Fig. 2, serves to render the manual control operative andpermit d a jogging ofthe work rotation, as desired. By

manipulation of the push buttons 203 and 204 and the snap switches 205and 206, the rotation of the work drive motor 45 may be readilycontrolled, as desired.l When the control switches are set for automaticoperation, the movement of themain control lever |80 Yinto the positionshown in Fig. 2 serves to render the cam |90 and the follower roller |88operative, so that the motor 45 will be stopped -in a predeterminedposition `and the work holders 51 and 58 'will be stopped in an uprightor loading position.

rIfhe operation of the machine is readily apparent from the foregoingdisclosure.

the. workfheads 51 and 58 -to 'be stopped in'a loading position and thecontrol lever |80 to be intheposition illustrated in Fig. 2,' acrankshaft 23 to' be ground is placed in position with the journalbearings 5| and 62 at its opposite ends resting uponthe supportingbearing surfaces 59 and 60, respectively, .Onthe heads'51 and 58. The

.operator then -shifts the control lever-'|10 of the reversing switch|69 into position. |10ato start 'the' rotation of .the work clampingmotors |30 :and-'|3l which serves, through the, reduction gearV4mechanism above described; to rotate the c ams12 and- |02 which inturnrock the clamp-v ing jaws'85 and 95 vto lock the crankshaft securely inoperative position en the opposed heads 51 and 50, respectively. 4Duringthe shifting movement of the lever into position 10a, the

lever |10 'engages the lug |19('Figs. 2 and 17) and rocks the `cam |11in a counterclockwi'se direc- -tion (Fig. 2) which serves to close ,thelimitswitch |15. `Inthis'pos'ition of the parts, the main control lever|80 may. then be rocked'in a counterv clockwise direction (Fig. 2) to"start the work rotation andthe grinding cycle. When the lever |80 isrocked from the position illustrated inV Fig.

2, the cam withdraws from engagement with the K roller |83 oflthemlimitswitch |84 and allows the limit switch '|84 to close, thereby energizing`the solenoid |85 which'in turnA rocks the arml |81 and' by traversingthetable longitudinally to position the next aligned crankpin inposition for thearm |98 tofallow the trip switch |91! `to close, fj Ythereby starting `the 4rotation ofthe workfdrive motor" 45. The grindingoperation maythen be continued .until vthe pin has .been ground, afterwhich any other pins on 'the shaft'may-be ground.t 35v grinding, Afterall of the aligned pins have'beenlv i ground, vthe-lever |80 may againbe shifted into the position shown iriFig. 2 which serves through thecam |9| and its associated parts and the motor brake switch |95instantaneously to reverse the direction of flow of current to the motor-to bringthe motor to an instantaneous stop. In this position, the limitswitch |84 has been opened and the limit switchA |1| closed so that thelever |10 of the reverse switch ||i9 .may be shifted from position |10into position 10b.

During this movement of the control lever |10, the lever engages the lug|18 and continued movement of the lever |10 shifts the cam v|11 in aclockwiserdirection--so that the roller |16 rides' 'l over the highpoint of the cam V|11 and again recedes to a suillcient extent to openthe limit switch |15, thereby breaking the circuit and deenergizing thesolenoid |85 so as to open the trip switch |92 and prevent starting ofthe work rotation during-the time the heads are unclamped.

The crankshaft may Vthen be indexed by rotat.

ing the indexing plate 20 in a dounterclockwise direction until the nextnotch |22 travels by the index or locating pawl |23 and the plate |20 isthen moved in a clockwise direction until thelocating surface of thenotch 22 engages the index or locating pawl. The lever |10 may then beshifted into position |10a which serves again to shiftl the cam |11 andto close the limit switch |15 and at the same time start the rotation ofthe clamping motors `to again clamp the crankshaft in position for thenext operation on the shaft. In case the electric power fails, themagnetic'switch 202 opens and before the machine can be again started,it is necessary for the loperator to close the push button 203 to'againoperate the magnetic starter switch 202.

By actuating the push button 204 and the snap switches 205 and 206, thework heads mayvbe either continuously rotated automatically under thecontrol of the main control lever, or if desired the work heads may bejogged or inched by means of the jogging button 204i.

It will thus be seen that there has been provided by this inventionapparatus in'which the various objects hereinabove set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmanypossible embodiments may be made of the above invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matter hereinbefore set forth or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

l. A work supporting and rotating mechanism for a grinding machinecomprising arotatable spindle, means including an electric motor torotate said spindle, means including a clamping jaw and an opposed workbearing member which is rotatable with the spindle to support a workpiece thereon, an electrically operated device to operate said jaw,manual means to control said motor, a manually operable reversing switchto operate said electrical device and clamping jaw, and an electricalinterlock including a limit switch associated `with said reversingswitch to prevent the clamping member from being disengaged before thework rotation motor has been stopped.

2. In a crank grinding machine, work clamping and supporting meanscomprising a jaw pivoted to grip the work eccentric with respect to itsaxis of rotation, said jaw being mounted on a lever extending at rightangles to the axis of rotation of the work, a rotatable cam 'foractuating said jaws, and electrically operated means including areversibleelectric motor for simultaneously actuating said cams and jawssimul taneously to clamp or release a work piece.

3. A work supporting and rotating mechanism for a grinding machinecomprising a rotatable spindle, means including an electric motor torotate said spindle, a work supporting head including a clamping jaw andan opposed work bearing member rotatable with said spindle to support awork piecethereon, a cam on each head for actuating said jaw, meansincluding an electric motor to operate said cam and jaw, manual meansincluding a switch to control said spindle rotation motor, meansincluding a reversing switch to control the second motor, and meansincluding a limitl switch associated with said reversing switch and saidfirst switch necessitating movement of l the clamping jaw to engage thework before the rst motor can be started to rotate the spindle.

4. In a crank grinding machine having a grinding wheel, a work carriage,opposed crank heads on the carriage and rotary spindles on said crankheads, crank clamping means comprising pivoted levers each having Workengaging jaws mounted therein, electrically operated means for movingsaid jaws simultaneously to crank engaging position, and means actuatedthereby including a hammer-blow mechanism for rapidly releasing a workpiece therefrom.

5. In a crank grinding machine having a grinding wheel, a work carriage,opposed crank heads-` on the carriage, rotary spindles on said crankheads, crank clamping fixtures comprising pivoted levers with workengaging jaws thereon, and

electrically operated means including a rotatable cam for operating saidlevers.

6. In a'crank grinding machine having a grinding wheel and opposed crankheads, work supporting and driving means comprising a lever extending at.right angles to the axis of rotation of the work and having a workgripping jaw, a rotatable cam on each of said heads arranged to actuatesaid jaws, electrically operated means including an electric motor oneach of said heads and arranged to actuate said cams, and means foroperating said motor simultaneously to actuate said cams to grip orrelease a work piece.

'7. Ina grinding machine, a pair of opposed heads, means for holding thework between said heads comprising a lever on each head, a jaw on saidlever, a rotatable cam on each head which is arranged to actuate saidlever to clamp or release the same, electrically operated meansincluding an electric motor on each of said heads, operative connectionsbetween said motor and saidvcam for actuating the clamping jaws, andmeans for simultaneously operating said motor simultaneously to clamp orrelease said jaws.

8. In a crank grinding machine having a grinding wheel, opposedrotatable crankshaft supporting heads, a lever on each head having agripping jaw, a rotatable cam on each head, a rotatable shaft withineach head to support said cams, and electrically operated meansincluding an electric motor for simultaneously rotating each of saidshafts and cams and simultaneously applying pressure equally to saidgripping jaws.

9. In a crank grinding machine having a grinding wheel, a work carriage,opposed crank heads on said carriage, a hollow rotatable spindle on eachof said crank heads, crank clamping fixtures on said shaft, a movablejaw in each fixture, a rotatable cam on each head arranged to actuatesaid jaws, a rotatable shaft to actuate each of said cams and extendingaxially within each spindle, an electric motor on each of said headswhich are operatively connected to rotate said cams to clamp or releasea work piece, and a single control for simultaneously actuating each ofsaid 10. In a crank grinding machine having a grinding wheel, a Workcarriage, opposed crank heads on the carriage, rotatable spindles onsaid crank heads, crank clamping fixtures on said spindles, a movablejaw in each xture, a rotatable cam on each xture which is'arranged toactuate the jaw, actuating means for said cams extending axiallywithineach of said spindles, a motor on each of said heads which are connectedto actuate said c'ams to clamp or release a work piece thereon, areduction gear mechanism interposed between each motor and cam, and asingle control switch to simultaneously stop or start said motors ineither direction.

'.11. In a, crank` grinding machine having a grinding wheel, a Workcarriage, opposed crank heads on said carriage and rotatable spindles onsaid crank heads, crankshaft clamping means comprising pivoted levers oneach head having work engaging jaws mounted therein, a cam on each headfor actuating said levers, and means including an electrically operatedmechanism for simultaneously actuating said cams and moving said jaws toor from a clamping position.

l2. A Work Supporting and rotating mechanism for a grinding machinecomprising a rotatwble spindle, means including an electric motor torotate said spindle, means including a clamping jaw andan opposed workbearing member die on said table for supporting a work piece, a worksupporting head on said spindle, a movable clamping jaw revolving withthe head and cooperating therewith to hold the work piece on said head,a cam on said head for actuating said jaw, an electrically operatedmechanism including an electric motor which is mounted to rotate withsaid spindle, and connections between said motor and said cam to actuatesaid clamping jaw.

, HERBERT A. SILV'EN.

CARL G.- FLYGARE.

